To which I say:
1. Your prosecutors are lazy and want to force criminals to prosecute themselves.
2. If the only external evidence of a crime is a private file on a hard drive, it seems to me that not much harm was done to society and we should leave these people alone.
It's worth it to trade letting some guilty people get away with it in order to have the freedom of conscience to write whatever we like in our computers and not be compelled to turn over our private writings.
If something bad was done to someone else, there's going to be evidence of it elsewhere: Contracts must be held by some other party, bank records, etc.
Is the prosecutor trying to claim the government needs access to the accused computer to convict her of a commercial crime? Are there no third parties involved who are in possession of useful records? No banks were involved in this mortgage fraud? Really???